Underground Fuel Storage Tanks vs Aboveground Fuel Storage Tanks
When choosing a storage tank for your company, one of the first major design decisions you must make is whether to install an above ground or below ground storage tank. While both have their benefits, installing the improper one for your facility’s needs can undermine the benefits of having a storage tank on-site.
In general, tanks like these are used to store fuel or other hazardous chemicals that your company needs on-site. Having a good sense of what your plant needs, your general plant layout, and what kind of storage flexibility you need will go a long way to helping you decide which type of tank you need. In this article, we will go through the pros and cons of each tank style and give you a better sense of which one to choose for any given situation.
Underground Fuel Storage Tanks
We’re going to start by outlining the characteristics of underground fuel tanks. As you might suspect, an underground fuel tank will take a lot more planning and will be less flexible, but depending on your needs, some of the benefits far outweigh the drawbacks. In general, if space on your plant grounds is of primary importance, an underground tank might be your best option, but let’s dive into the pros and cons.
The very nature of an underground storage tank means that the tank itself is significantly more protected than an aboveground tank. Underground tanks are far less exposed to weather events, temperature changes, and corrosive environmental factors, which will reduce your repair and maintenance bills and extend the life of the tank. Moreover, such tanks are less likely to be tampered with or vandalized, which can be a problem with above ground tanks, especially those near the perimeter of a facility.
Underground tanks also have certain inherent design benefits which make them safer. Much of this is tied to the ground insulating underground storage tanks from temperature fluctuations. Fewer temperature fluctuations reduce the possibility of fuel or gas expansion, which can lead to a pressure build-up or explosion. In the worst case, an underground tank fire is likely going to be easier to manage and contain, thanks again to the barrier that the ground provides.
Finally, the tank is underground and out of the way after installation, ensuring that you have more room for other vital equipment in your plant’s layout. A large underground tank can do the job of several aboveground tanks, which frees up a significant amount of floor space for your plant.
As apparent as the operational benefits of an underground storage tank are, they do not come without their costs.
Right up front, the installation cost, the intensity of the planning stage, and the length and intensity of disruption caused by the installation are far higher with underground tanks. Not only do you have to clear the space for one, but you also have to remove the soil from the area where it will go, which can be difficult depending on how firm the soil is around your plant (particularly in areas where you have to consider the winter frost layers). It is also not enough to just install the tank, but you have to install the piping system and the access routes to the tank if you ever have to perform repairs. With this increased installation intensity comes higher levels of regulation, more permits, and more equipment.
On top of this, once you install a tank, it can be harder to notice any potential leaks as they are happening. By the time you notice, it may be too late, and the leaks may have seeped significantly into the surrounding soil, which comes with considerably heavier fines than a surface leak. The repairs, in such events, are also more difficult to manage, particularly if you did not install extensive access channels.
Finally, if you choose to install an underground tank, it will be very difficult to move it or shift your plant layout around it, so you should make sure that you are confident in your plans and knowledge of local regulations before committing to such an installation.
Aboveground Fuel Storage Tanks
Aboveground storage tanks tell a different story. Their upfront costs tend to be lower, and their installation and operation are more flexible and visible, but they come with their drawbacks. Let’s take a look.
Unsurprisingly, it is much easier to plan for and install an aboveground fuel tank. While you cannot fully install them in a day, they do certainly go up faster than underground tanks, if only for significantly reduced excavation times. This ease extends to maintenance, as it is much easier to both observe and repair these tanks. The reduction in these costs is not negligible, and this ease of use is a major benefit.
Given their visibility, it is very difficult for a leak to occur without someone noticing, so you can initiate cleanup more rapidly and more effectively in the case of any spills. The direct cleanup costs will be lower, as will the savings from avoiding any violation of local spillage regulations. In addition, vents and other piping are easier to access and less likely to be interfered with at ground level, reducing maintenance costs.
On top of this, if your plant’s ground plans ever change, aboveground tanks can be more easily moved around. Their installation effort is a significantly smaller sunk cost. Some can be designed for portable operations, which, although an extreme case, is a good representation of the overall flexibility benefits of aboveground tanks.
While aboveground tanks are prevalent due to the above benefits, there are some drawbacks to relying on them.
To begin with, their exposure to weather and the elements introduces the two-pronged attack of contamination of product and corrosion of the tank exterior. Exposure to water, heat, and air increases the risk of contamination, loss to expansion and venting, and a general reduction in fuel storage life. The elements act more quickly to break down the exterior of the tanks, fiberglass or metallic, through corrosion, UV exposure, or other effects. This increases maintenance costs and comes with the unique cost of repainting and reapplying protective coatings every 5-10 years.
This lack of insulation from the ground also introduces a higher risk for fires or explosions. This risk requires the installation of more extensive vapor recovery systems and the passing of a host of more stringent inspection regulations. These regulatory concerns include the location of the tanks relative to the rest of the plant, given that this fire risk needs to be quarantined by distance rather than an earthen barrier. Without that barrier, there are more explosion risks, and the regulatory framework takes these increased risks seriously.
Which Fuel Storage Tank is Right For Your Plant?
If you are looking to store fuel at your plant, you are going to have to decide between an aboveground and a belowground tank. Depending on which tradeoff makes more sense for your plant, based on layout, investment costs, safety regulations, relative risks, flexibility, and varying levels of maintenance expertise, you can certainly argue for either system.
On the whole, both tanks can last for decades. Underground tanks are more costly, but require less maintenance if installed correctly, while an above ground system is good for flexible operations on a large plant footprint.
Hopefully, this article has helped give you a framework for thinking about that choice in the case of your plant. Regardless of which tank you choose, you cannot ignore either internal or external maintenance. You can always benefit from robotic tank cleaning and sludge removal for internal maintenance. For all of your tank cleaning needs, take a moment to explore some industrial storage tanks that can benefit from robotic tank cleaning.